Method of making metallic tube-joints.



G. HOLDEN.

1 1914- 1,168,885. Patented Jan. 18, 1916.

fT STAE ABN FFEO,

GEORGE HOLDEN, OF FLUSI-IING, NEVV YORK, ASSIG'NOB, T0 THE NEWARK SPRINGMATTRESS COMPANY, A CORPORATION OF NEW JERSEY.

METHOD OF MAKING METALLIC TUBE-JOINTS.

Application filed January 13, 1914.

- mode of operation, all as will be more fully hereinafter set forth, asshown in the accompanylng drawing, and finally pointed out in theappended claims.

In the accompanying drawing Figure 1 is a view in transverse section ofa form of die and presser roll employed in carrying out the principlesof my invention. Fig. 2- is a similar view sho-wing the application tothe die of a. metallic split tube and a seam or joint insert thereforpreparatory to the application of pressure to complete the joint. F ig.3 is a view similar to F ig. 2 showing the form assumed by the samejoint upon application of pressure. Fig. Li is an end view of a metallictube having a scam joint constructed according to and embodying theprinciples of my invention. Fig. 5 is a broken view in transversesection through the seam joint.

In carrying out my invention I bend or fold the longitudinal edges of asplit metal tube, respectively in opposite directions away from eachother and I form an insert or auxiliary seam piece with its longitudinaledges bent respectively toward each other to produce a channel formationthe bent edges of the split tube being received in the side or edgechannels of the auxiliary piece. I then apply pressure to the joint thusformed and in such manner as to force or crowd the metal constitutingthe engaged portions of the tube edges and the auxiliary strip intosubstantially an integral mass, and at the same time crowding the metallaterally toward the center lline of the joint, thus forming a perfectjoint for the split tube, and a joint that is strong and durable. Thetube may be cylindrical or of any other desired shape in crossfsection.

In the drawing 6 designates the cylindri- Epecfication of LettersPatent.

Serial No. 811,836.

cal metal tube which is longitudinally split.

The longitudinal edges 7, 8 of the split tube are then bent respectivelyin opposite directions with reference to each other and preferably,though not necessarily, toward the interior of the tube. 1 then take anauxiliary strip 9 of metal and bend the side edges 10, 11 thereof towardeach other and in opposite directions respectively with reference to thebent edges 7, 8 of the split tube. The extra strip is then applied insuch relation or slipped over the bent edges 7, 8 in such manner as tocause the bent edges 10, 11 of the strip to embrace and engage over thebent edges 7, 8 of the tube. VVith the scam thus preliminarily formed,pressure is applied thereto in such manner as to not only compress thecomponent parts thereof into a substantially solid mass of metal butalso in such manner as to crowd or force the metal of the auxiliarystrip and of the tube edges laterally toward the center line of thejoint. One method of accomplishing this is to employ a inandrel or die12, preferably but not necessarily of oval shape in cross section andover which the tube with the scam parts thereof arrang'ed as aboveindicated is slipped endwise. In the form shown the mandrel or die hasthe portions ofthe peripheral surface thereof indicated at 13 and 14Fig. 1, and lying between the radii indicated at 15, 16, and 17, 18respectively of circular contour in cross section, the center of thecurvature being concentric with the geometric axis of the mandrel. Thedie or mandrel is formed with a seat or recess indicated at 19 toreceive the preliminarily formed scam.

One of the important features of my invention, whereby 1 am enabled toaccomplish my objects and purposes in carrying out the principles of myinvention resides in the peculiar shape and contour of the die seat orrecess 19. This feature is the curved surface indicated at 20 and thefeature of peculiarity thereof is that the arc of curvature of thissurface is eccentric to the arc of curvature of the peripheral surface13 of the die, that is to say, the arc of curvature of the surface 20 isstruck from a center, as indicated by the dotted lines 21 in Fig. 1,which is eccentric with reference to the geometric axis of the die, andpreferably having a radius of less length than that of the circularportion 13 of the die. Another fea- Patented J an. 18, 1916.

j ture is that the space at the transverse cenor otherwise in adirection normal to the line of the seam, as indicated in the drawing tocomplete the formation of the joint, the metal forming the auXiliarystrip and its over turned edges, as well as the engaging parts of theturned over edges of the tube, are thereby pressed into a substantiallyintegral mass. .Under the pressure thus applied in a direction normal tothe line of the seam the metal of the parts forming the joint whilebeing pressed into an integral mass is forced into the corner pockets ofthe recess or seat 19 until said corner pockets become filled whereupon,by reason of the eccentric surface 20, a continued application of thepressure in a direction normal to the line of the seam produces apressure upon the mass of the metal 'of the joint which is applied in adirection laterally toward the line of the seam and from opposite sidesthereof, whereby the metal is crowded laterally toward the longitudinalcenter line of the joint so as to fill up completely the space betweenthe overturned edges of the split in the tube. As indicated in Figs. 4and 5 the curif'ature indicated at 25 in the finished article is of lessradius than the curvature of the interior surface of the tube.

It will be understood that the crowding of the metal toward the centerline of the seam is secured, as above described, by a secondary pressurewhich i's applied to the metal by reason of the peculiar conformation ofthe seat or recess into which the metal is forced by the crushingpressure exerted by the member 2%, and that this secondary pressure isdirected toward the center line of the seam, and while I will call thisa lateral pressure or crowding action eXerted upon the metal, I wishthereby, in the broadest interpretation thereof to distinguish from thenormally applied primary or crushing' pressure of the member 24:.

' In the manner above described, I secure a solid integral joint whichis stro-ng and durable. Metal tubes having longitudinal seam j ointsformed and constructed as above described are well adapted for use inthe Construction of various articles.

Having now set forth the object and nature of my invention and thelmethod of carrying the same into operation, whatr I claim as new anduseful and of my own invention and desire to secure by Letters Patent ofthe United States is:

1. The method of forming seam oints for metallic tubes which consists inbending the edges of the tube in opposite directions away from eachother and applying thereto an auxiliary strip having its longit'udinaledges oppositely bent toward each other and engaging over the bent edgesof the tube, and then. compressing the metal of the component parts ofthe resulting seam joint into a substantially integral mass toward thecenter line of the joint in directions normal to and also from thelaterally opposite sides of said line.

2. The method of forming seam joints for metallic tubes which consistsin bending` the edges of the tube seam in opposite directions from eachother and applying an auxiliary strip with oppositely turned fianges inembracing relation with respect to the bent edges of the tube, and thenapplying pressure to the assembled components of the joint in adirection toward and normal toi the line of the seam and also from thelaterally opposite sides of and toward the seam line, therebycompressing the metal of the component parts of the joint into asubstantially integral mass.

3. The method of forming seam joints for metallic tubes which consistsin bending the edges of the tube seam in opposite directions from eachother and applying an auxiliary metal strip with oppositely turnedfianges in embracing relation with respect to the bent edges of thetube, then applying pressure to the assembled components of the joint ina direction toward'and normal to the line of the seam, and unyieldinglyresisting such pressure, and also applying pressure toward the line ofthe seam from the laterally opposite sides thereof, whereby the metal ofthe component parts of the joint is compressed into a substantiallyintegral GEORGE HOLDEN. VVitnesses NV. A. DARBY, G. A. MCGRATH.

Copies of this patent may be obtained for five eents each, by addressngthe Commissoner of Patents,

i Washington, D. 0.

